The present invention relates to a method of printing on a curved surface of a material to be printed. This kind of conventional printing method, as described in the specification of the U.S. Pat. No. 4,010,057, depends on a technique by which an inflatable film on which a transcription pattern is printed in advance is kept afloat on water, to be expanded and impressed by a material to be printed to be immersed into water, and the film is adhered to the material to be printed by virtue of water pressure while the film is extended.
However, the conventional method is disadvantageous in that it is difficult to supply the film since it should be kept stationary on the water surface, a favorable print cannot be obtained if the timing of impression of the material to be printed is delayed since the film begins to extend and expand as soon as it contacts water, it is troublesome to impress the material to be printed against the film, and the printing of the pattern on the specified position of the material to be printed is difficult.